Electrode saving attachment for carbon arc lamps



R. HANOVER 2,584,579

ELECTRODE sAvTNG ATTACHMENT FOR CARBON ARC LAMPS Feb. 5, 1952 Filed May '7, 1951 I N VE N TOR Eme/z /fd/mref" ATTORNEY Patented Feb. 5, 1952 UNITED STATES PATENT OFFICE ELECTBODE SAVING ATTACHMENT FOR CARBN ARC LAMPS 3 Claims.

In the production of jgzlctures, be they of the still or of the moving picture type, a powerful arc lamp is used. Such arc lamp includes a reflector, a feed mechanism behind the reflector for feeding the cathode through an opening in the center of the reector and a feed mechanism on ythe opposite side of the reflector for feeding the anode toward the cathode to maintain the desired gap between the coacting ends of the cathode and the anode. Because the arc must be a predetermined distance from the center of the reflector and because, due to obstructions present, the feed mechanism which carries the anode can not'inove toward the reflector beyond a .given point, it is only possible to burn the cathcdes and the anodes to within a few inches of their respective ends. This leaves 'a stump which is wasted. The cathode is a solid rod and is of a relatively smaller diameter. It is therefore relatively less expensive. The anode is tubular in cross section and is of a relatively7 large diameter and is therefore relatively more expensive.

It is therefore an object of the invention to produce an improved feed mechanism whereby the relatively long stumps of the anode which would otherwise be left unconsumed may be burnt almost to their ends thus eifecting considerable reduction in ,the waste now attending the projection of pictures and particularly moving pictures.

Also, as presently constructed, the anode feed mechanism includes a fixed support which is located in front of the reflector and is therefore in the path of the reflected light. Due to the intensity of the light this xed support does not throw a visible shadow but it does adversely affect the distribution of the light.

It is therefore a further object of the invention to produce an improved feed mechanism in which the light obstructing support above referred to is eliminated.

The anode is made long enough so as to last through the projection of a standard or average reel of film and, in order not to have to make the anodes too long, a very narrow margin of safety is provided. Furthermore, because testing or adjustment .may be needed, or because some very short reel is projected which consumes only a small portion of the anode, or because the length of the reel or its rate oi travel, the rate at which the anode is consumed may vary, the anode may be consumed as far as it is practicable to burn it, before the reel is finished with a resulting interruption which is obviously disadvantageous.

It is therefore a further object of the invention to provide an improved feed mechanism, by means of which a remnant, or stump which is leit after an anode as far as conventional apparatus permits, has been consumed may be further burned, in sequence with a full length, or with a partly used anode, whereby the length of the stump plus the length of the anode proper will be ample to insure complete projection of a standard reel the presence of one or more of the variables above set forth notwithstanding.

These and other objects are attained by my invention as set forth in the following specincationfand as shown in the accompanying drawings in which:

Fig. l is a view, partly in vertical section and partly in side elevation showing my improved anode feed mechanism, in one position thereof, only so much of the projection apparatus proper being shown as is necessary for an understanding of the invention.

Fig. 2 is similar to Fig. 1 showing the feed mechanism in a second position thereof.

Fig. 3 is a sectional view taken on line 3-3 on Fig. l, showing details of construction.

Fig. 4 is an enlarged section on line 4-4 on Fig. l showing details of construction.

The projection apparatus illustrated includes a suitably mounted reflector Ill in the center of which is an opening l2 for the passage therethrough of a cathode it. The cathode is carried by a clamp l at the top of a carriage I8 which is moved from right to left, as viewed in Figs. 1 and 2, by means of a conventional feed mechanism which is generally designated by reference numeral 2li. The apparatus further includes a carriage 22 which is actuated towards, and away from, the reflector lil by means of a conventional feed mechanism which is generally designated by reference numeral 2li.

To the carriage 22 is pivoted, as at 25, a casting 28 for supporting the anode 30. The anode is suitably secured in position by being clamped between an upper movable jaw 32 and a lower fixed jaw 3ft which is formed at the top oi casting 28. The upper jaw 32 is raised and lowered by a suitable means, which is not shown in detail but which is actuated by turning handle 38 in the appropriate direction. When casting 2&3 is in the position of Fig. 2 the surface lidv thereof abuts surface A2 on carriage 22 so as to maintain the casting in a position in which the anode will register with the cathode.

In order to reduce waste and in order to supple'ment the anode 3&3, I provide means for carrying a discarded stump or short piece of anode 46 to be burned before anode 3D is burned. The means for carrying the stump 46 includes an upper movable jaw 32X similar to jaw 32 and a lower fixed jaw 34X, the upper jaw being actuated by turning handle 38X in the appropriate direction. It will be noted that the relation of the jaws 32X and 34X to jaws 32 and 34 is such that, when the carriage 22 is in the position of Fig. l, the anode stump 46 is horizontal, or in registration with the cathode, the main anode 30 will assume an inclined position. Likewise. when the carriage 22 is in the position of Fig. 2, the main anode 30 will be in registration with the cathode and the remnant of stump 46 will assume an oppositely inclined position.

In order to maintain carriage 22 in the position of Fig. l during the burning of the stump 46 and to permit the carriage automatically to move to the position of Fig. 2 to bring anode 30 to operative position, I provide a trip arm 50 which is pivoted at 54 and which is preferably spring loaded so that the hooked upper end 54 of arm 50 will engage a hole or recess 56. In other words, as long as the upper end 54 of arm 50 is in recess 56, casting 22 will be in the position of Fig. l. In order to disengage trip arm 50 I provide an ovaloid nut 66 which is so located relative to the motion of carriage 22 toward the reflector I0 that the lower end 62 of trip arm 50 will ride up the inclined face 64 of the nut 6U and the arrangement is such that, when the lower end 62 of arm 50 rides on the high point 66, the upper hooked end 54 of the trip arm will be withdrawn from recess 56. This permits casting 22 to drop from the position of Fig. 1 to the position of Fig. 2. The nut 60 is carried by, and threadedly engages a worm 68 and the position of the nut 60 on worm 66 is determined by the length of the stump 46. In other words, the nut 66 is moved along so that, when jaw 32X and 34X have moved towards the lens as far as permissible, the arm 50 will be tripped by nut 60 and casting 22 will move to the position of Fig. 2 in which anode 30 will begin to burn.

By thus burning a stump 46 before beginning L to burn a main anode 30, the waste represented by discarding stump 46 will be reduced and there will be assurance that main anode 30 will outlast the reel to be projected even if the reel is a little longer than usual or if the anode should burn at a little faster rate than usual. Also, for testing, for adjusting and for projecting very short pieces of i'llm, a stump 46 may suiiice thus making it unnecessary to use any part of the main anode 30 prior to commencement of projection of the main reel. Also, by the arrangement shown, the conventional permanent support, which has heretofore been used in addition to the carriage 22, is eliminated and the interference with the light distribution is reduced.

What I claim is:

1. For use in connection with a film projection apparatus of the type which includes a reflector, a first carriage located to the convex side of the reflector and adapted to support a horizontal cathode, means for moving said carriage toward, and away from, said reflector, there being an opening in said reilector through which said cathode may pass, a second carriage located to the concave side of said reflector and a means for moving said second, carriage toward, and away from said reilector, a casting pivotally secured to said carriage, a rst jaw carried by said casting for supporting a relatively long anode, and a second jaw carried by said casting intermediate said ilrst jaw and said reilector and adapted to support a relatively short anode, the vertical axis of said second jaw being at an angle to the vertical axis of said first jaw, said casting being movable to a iirst position in which the relatively short anode in said second jaw is in alignment with said cathode, and said relatively long anode is out of alignment with said cathode, and to a second position in which said relatively short anode is out of alignment with said cathode and said relatively long anode is in alignment with said cathode and said relatively short anode is out of alignment with said cathode.

2. The structure recited in claim l together with means for automatically moving said casting from said first to said second position.

3. The structure recited in claim 2 in which the means for moving the casting is in the nature of a trip mechanism together with means adjustably interposed in the path of movement of said casting for releasing said trip mechanism.

ROBERT HANOVER.

No references cited. 

